Preferential Adsorption Research Articles

E-beam fluorinated CVD graphene:in-situXPS study on stability and NH3adsorption doping effect.

Graphene exhibits promise in gas detection applications despite its limited selectivity. Functionalization with fluorine atoms offers a potential solution to enhance selectivity, particularly towards ammonia (NH+) molecules. This article presents a study on electron-beam fluorinated graphene (FG) and its integration into gas sensor platforms. We begin by characterizing the thermal stability of fluorographene, demonstrating its resilience up to 450 °C. Subsequently, we investigate the nature of NH3interaction with FG, exploring distinct adsorption energies to address preferential adsorption concerns. Notably, we introduce an innovative approach utilizing x-ray photoelectron spectroscopy cartography for simultaneous analysis of fluorinated and pristine graphene, offering enhanced insights into their properties and interactions. This study contributes to advancing the understanding and application of FG in gas sensing technologies.

Ligand-Mediated Surface Reaction for Achieving Pure 2D Phase Passivation in High-Efficiency Perovskite Solar Cells.

The surface passivation with the heterostructure of the 2D/3D stack has been widely used for boosting the efficiency of n-i-p perovskite solar cells (PSCs). However, the disordered quantum well width distribution of 2D perovskites leads to energy landscape inhomogeneity and crystalline instability, which limits the further development of n-i-p PSCs. Here, a versatile approach, ligand-mediated surface passivation, was developed to produce a phase-pure 2D perovskite passivation layer with a homogeneous energy landscape by dual-ligand codeposition. The preferential adsorption of 3,6-dimethyl-carbazole-9-ethylammonium iodide with a large molecular size and lower adsorption energy could regulate the surface reaction between the m-fluorophenylethylammonium iodide and perovskite surface, resulting in a 2D perovskite with a narrow quantum well distribution and a uniform surface potential distribution. Beyond this, the preservation of the surface-confined 2D passivation layer retained a higher electric field at the interface of perovskite and the hole transport layer. As a result, the champion device reached an efficiency of 25.86% for the 0.05 cm2 device and 25.08% for the 1 cm2 device, with enhanced operational stability (T90 > 1000 h) and much better thermal stability. Our work provides deeper insights into efficient and stable 2D passivation for PSCs.

First-Principle Calculations on O-Doped Hexagonal Boron Nitride (H-BN) for Carbon Dioxide (CO2) Reduction into C1 Products

With the rapid growth of the world population and economy, the greenhouse effect caused by CO2 emissions is becoming more and more serious. To achieve the “two-carbon” goal as soon as possible, the carbon dioxide reduction reaction is one of the most promising strategies due to its economic and environmental friendliness. As an analog of graphene, monolayer h-BN is considered to be a potential catalyst. To systematically and theoretically study the effect of O doping on the CO2 reduction catalytic properties of monolayer h-BN, we have perform a series of first-principle calculations in this paper. The structural analysis demonstrates that O preferentially replaces N, leading to decreasing VBM of monolayer h-BN, which is conducive to improving its capability for CO2 reduction. The preferential CO2 adsorption sites on monolayer h-BN before and after O doping are the N-t site and B-t site, respectively. O doping increases the adsorption strength of CO2, which is favorable in the further hydrogenation of CO2. During the conversion of CO2 into CO and HCOOH via a two-electron pathway and CH3OH and CH4 via a six-electron pathway, O doping can reduce the energy barrier of the rate determining step (RDS) and change the key steps from uphill reactions to downhill reactions, thus increasing the probability of CO2 reduction. In conclusion, O(N)-doped h-BN exhibits the excellent CO2 reduction performance and has the potential to be a promising catalyst.

Transition from Internal to External Oxidation in Binary Fe–Cr Alloys Around 900 °C

The transition from external to internal oxidation of a binary Fe-10Cr alloy has been investigated in Fe/FeO Rhines pack (RP) and H2/H2O between 850 and 900 °C. Internal oxidation is facilitated by increasing temperature and presence of water vapor. A classical Wagnerian diffusion analysis predicts external oxidation for ferritic (BCC) Fe-10Cr and internal oxidation for austenitic (FCC) Fe-10Cr. The α-to-γ transformation is demonstrated to be the primary factor promoting internal oxidation in Fe–Cr around 900 °C. Water vapor is believed to promote internal oxidation due to a higher reactivity of H2O compared to O2 and higher preferential adsorption of the H2O molecule.

Unraveling the modulation art of ordered nanomesh-like hydration product on fiber-cement interfaces: Insights from fishing net inspiration

The morphology of interface hydration products is crucial as it directly determines the interface mechanics. Inspired by the fishing nets, we employed photo-grafted active copolymer Poly(vinylpyrrolidone-co-acrylic acid) on the inert glass fibers. Providing a template for PVP-co-PAA maintains its regulatory capability in cement paste. For the first time, ordered nanomesh-like hydrated calcium silicate (CSH) with average pore diameter of 30 nm are developed in cement paste. The interface strength and energy absorption increased by 90 % and 253 %, respectively. XPS and SEM revealed that the multi-scale regulation mechanisms originated from the preferential adsorption and stable dispersion of Ca2+ result from the strong electronegativity and steric hindrance of pyrrolidone rings. CSH nuclei (60 nm) dispersed well on fiber templates, stacked along fiber surfaces, without collapse or tilt, intertwined into nanomesh. Nanomesh-like CSH in cement paste holds significant potentials for the improvement of mechanical properties of fiber-cement interfaces, contributing to construction sustainability.

Using δ65Cu and δ34S to determine the fate of copper in stream waters draining porphyry mineralization: Implications for exploration targeting

The fate of metals, such as Cu, in stream waters draining porphyry mineralization is commonly controlled by several natural processes such as sorption, microbial processes, and ligand availability. Isotopes of Cu offer a novel approach to understanding these processes and determining metal sources within complicated mineralogical systems. Drainages at the Casino Cu-Au-Mo porphyry deposit, Yukon, Canada exhibit circumneutral (pH > 5) in Casino Creek and natural acid rock drainage (pH < 3.5) in Proctor Gulch with the precipitation of schwertmannite (Fe3+). Isotopic systems δ65Cu and δ34Ssulfate indicate different metal sources, with signatures of both hypogene and supergene mineralization. Waters from Proctor Gulch contain δ65Cu values (< −0.5 ‰) consistent with supergene Cu sources from the leached or oxide portion of the mineralization. Comparatively, drainage in the upper part of Casino Creek contains a δ65Cu composition (> 0.5 ‰) characteristic of Cu sourced from hypogene sulfide mineral oxidation. Variation in metal sources is similarly supported by aqueous δ34Ssulfate values in the stream waters, which suggest mixing of S derived from a sulfide mineral phase and a much heavier sulfate mineral (e.g., gypsum or anhydrite). Isotopic fractionation of Cu in the dissolved (<0.45 μm) phase presents two predominant controls on Cu dispersion. The natural acid conditions in Proctor Gulch favor the preferential co-precipitation of 63Cu with schwertmannite but could be influenced by intracellular assimilation or adsorption by microbes, which also has been shown to preferentially favor 63Cu. Copper isotopic fractionation results in a gradient of increasing δ65Cu values in waters downstream. In Casino Creek, higher pH conditions favor the precipitation of Fe(OH)3 and the preferential adsorption of 65Cu, resulting in decreasing δ65Cu values downstream. Copper concentrations in stream waters remain elevated (up to 4.1 μg/L) above ambient background (1.9 μg/L) levels up to 11 km downstream of the deposit. Given the abundance of surface water in many parts of northern Canada, hydrogeochemical prospecting using broad scale stream water catchment analysis is clearly a viable greenfield exploration methodology.

Probing the energy landscapes and adsorption behavior of asphaltene molecules near the silica surface: Insights from molecular simulations

Enhanced oil recovery (EOR) is a promising solution to meet the increasing energy demands. However, the efficiency of EOR processes is hindered by the deposition and precipitation of heavy oil components, such as asphaltenes, at various stages of oil extraction. Therefore, a detailed understanding of asphaltene molecules (AMs)–rock interactions is important for designing novel solvents and enhancing the efficiency of existing solvents in oil recovery. Using molecular dynamics simulations, we have investigated the structural and energetic behavior of model AMs in dodecane solvent near the silica surface representing the sandstone reservoirs. We obtained the potential of mean force of AMs (containing three island-type and two archipelago-type AMs), calculated their adsorption–desorption barriers, and compared them among themselves and with solvent molecules. We found a competition between AMs and solvent, where AMs with higher configurational energy than the solvent molecules exhibit preferential surface adsorption. We observed that the heteroatom-surface interactions play a pivotal role in the adsorption of AMs, such that AMs with polar heteroatoms prefer to adsorb onto the surface. Further, the desorption barrier of AMs was found to be proportional to the number of hydrogen bonds formed. We observed that the AMs anchored to the surface through the aliphatic chains lie parallel, whereas those with heteroatom adopt an orientation nearly perpendicular to the surface.

Force density induced by preferential adsorption in a near-critical binary fluid mixture subject to the Soret effect.

We assume that two parallel plates are immersed in a binary fluid mixture lying in the one-phase region near the demixing critical point and that the surface of each plate attracts the mixture components differently via short-range interactions. It is known that the composition inhomogeneity caused by the difference can induce a force exerted on the plate at equilibrium. In the present study, we investigate how a temperature gradient imposed vertically on the plates changes the induced force by calculating the composition profile subject to the Soret effect. Numerically solving the derived differential equation, we show that a temperature gradient within the critical regime can change the force distinctly from its equilibrium value and can make the force direction opposite to the one at equilibrium.

Metal-free N, P-Codoped Carbon for Syngas Production with Tunable Composition via CO2 Electrolysis: Addressing the Competition Between CO2 Reduction and H2 Evolution.

Electroreduction of carbon dioxide into value-added fine chemicals is a promising technique to realize the carbon cycle. Recently, metal-free heteroatom doped carbons are proposed as promising cost-effective electrocatalysts for CO2 reduction reaction (CO2RR). However, the lack of understanding of the active site prevents the realization of a high-performance electrocatalyst for the CO2RR. Herein, we synthesized metal-free N, P co-doped carbons (NPCs) for producing syngas, which is composed of H2 and CO, by CO2 electrolysis using inexpensive bio-based raw materials via simple pyrolysis. The syngas ratio (H2/CO) can be controlled within the high demand range (0.3-4) at low potentials using NPCs by tuning the N and P contents. In comparison with only N doping or P doping, N and P co-doping has a positive impact on improving CO2RR activity. Experimental analysis and density functional theoretical (DFT) calculations revealed that negatively charged C atoms adjacent to N and P atoms are the most favorable active sites for CO2-to-CO conversion compared to pyridinic N on N, P co-doped carbon. Introducing N atoms generates the preferable CO2 adsorption site, and P atoms contribute to decreasing the Gibbs free energy barrier for key *COOH intermediates adsorbed on the negatively charged C atoms.

Hydrophilic Modification of Macroscopically Hydrophobic Mineral Talc and Its Specific Application in Flotation.

Sodium diethyldithiocarbamate (DDTC), a common collector used to enhance the hydrophobicity of minerals in froth flotation, nevertheless weakens the hydrophobicity of the talc surface. To rationalize this anomaly, the interactions of a hydrophobic alkyl group and hydrophilic mineralophilic group (-NCS2-) of heteropolar surfactant DDTC, and a water molecule with the talc (001) surface, were investigated. Herein, DFT simulations found that the talc (001) surface features natural hydrophobicity determined by the competition between adhesion (surface water) and cohesion (water-water interactions). The interaction of the hydrophobic alkyl group of DDTC with the talc surface is more favorable compared to that of the -NCS2- group and H2O, favoring the hydrophilic modification of the talc surface. Additionally, adsorption isotherms, time-of-flight secondary ion mass spectrometry (ToF-SIMS), microflotation tests, and contact angle measurements also indicate that the differences in adsorption orientation of the heteropolar surfactant DDTC on the talc surface enhance the hydrophilicity of the talc surface, leading to a decreased recovery of the talc. This study provides crucial surface chemistry evidence for the selective adsorption of heteropolar surfactants and contributes to the understanding of the mechanism for the efficient flotation separation of molybdenite from talc.

Investigating adsorption properties of CO2 and CH4 in subbituminous coals from Mamu and Nsukka formations: a molecular simulation approach

The study aimed to investigate the adsorption properties of methane (CH4) and carbon dioxide (CO2) in subbituminous coals from the Mamu and Nsukka formations, focusing on the CO2-Enhanced Coalbed Methane (ECBM) method. Proximate, ultimate, and FT-IR analyses determined the quality, age, and functional categories of these coals, confirming their subbituminous nature. Using molecular dynamics (MD) simulations, a unique amorphous subbituminous coal model was developed to study adsorption phenomena. Isosteric heat and adsorption isotherms for pure CO2 and CH4 were analyzed, alongside Grand Canonical Monte Carlo (GCMC) simulations to assess CO2 adsorption selectivity in a binary CO2 and CH4 mixture. Results showed that CO2 required more isosteric heat than CH4 in single-component scenarios and demonstrated stronger electrostatic interactions with heteroatom groups in the coal model, explaining its higher adsorption preference. In binary adsorption experiments, CO2 exhibited a higher affinity under specific conditions, particularly influenced by pressure variations. At lower pressures, CO2 selectivity decreased rapidly with increasing temperature, while at higher pressures, the influence of temperature diminished. These findings have established a theoretical and practical basis for optimizing CO2-ECBM extraction in Nigeria, highlighting the preferential adsorption of CO2 over CH4 in subbituminous coals from the Mamu and Nsukka formations under varying pressure and temperature conditions. Implementing CO2-ECBM extraction and storage in Nigeria could boost economic viability and help achieve net-zero goals, using insights from this study to guide policy development.Graphical

Pristine B40 fullerene as a potential gemcitabine drug carrier for anti-lung cancer properties: a DFT and QTAIM study

Novel biomedical applications of various nanomaterials are being extensively researched as drug delivery systems. These nanomaterials deliver various anticancer treatments into the specific tumor cell sites, which reduces their terrible side effects. In this study, we have used DFT/B3LYP/6-311++G(d,p) level of theory to examine the efficacy of the pristine B40 fullerene (Boron) as a drug delivery vehicle for gemcitabine an anti-lung cancer medication at various position. From our investigation the most stable adsorption orientation was observed between double bonded oxygen atom of the drug and six membered ring boron atoms of B40 fullerene both in gas and solvent phases. The frontier molecular orbitals and QTAIM studies further support the interaction of gemcitabine medication with the B40 fullerene. NBO and MEP methods show substantial charge transfer from gemcitabine drug molecules to the fullerene. Overall, the results suggest that the B40 fullerene effectively adsorbs the drug and hence can be used as a tool for drug delivery system.

Computational insights into graphene-based materials for arsenic removal from wastewater: a hybrid quantum mechanical study

The discharge of industrial wastewater, particularly from chemical and mining industries, poses significant threats to the environment, public health, and safety due to high concentrations of pollutants leading to serious illnesses and the loss of aquatic life. It is therefore essential and urgent to devise measures for mitigating these threats. To advance the understanding of graphene membranes for Arsenic (As) removal from wastewater, this research investigates As adsorption and its relative selectivity on graphene-based materials using computational approaches. Our study employed hybrid quantum mechanical calculations for energy and geometry optimization to explore As adsorption on pristine graphene membrane surfaces in vacuum and aqueous environments. We assessed the effect of different adsorption sites on the surface which includes the top (T), bridge (B), and hollow (H) sites across the edge (E) and center (C) regions of the absorbent surface, to identify the optimal site/mode of adsorption. Our results demonstrate that the edge sites are the most effective for adsorption, exhibiting strong adsorption energies in both vacuum (− 1.98 eV) and aqueous environments (− 1.97 eV). These values are significantly higher than the adsorption energies for water on the surface, which range from − 0.25 to − 0.26 eV. Geometrical analyses confirmed the bridge edge sites as the most preferred adsorption configuration. Our findings not only advance upon existing computational approaches for designing efficient adsorbents but also provide deeper insights into the adsorption mechanisms on graphene-based materials. Unlike previous studies, which focused primarily on experimental or theoretical aspects in isolation, this work integrates computational and theoretical approaches to optimize adsorption processes at the molecular level. By investigating membrane properties for As removal, this research offers a novel pathway for developing advanced adsorbents, addressing critical challenges in environmental remediation with greater precision and efficiency.Graphical

Amorphous Ni3B Promotes Electroreduction of Nitrate to Ammonia.

The electrocatalytic nitrate reduction to ammonia (NRA) can address nitrogen cycle imbalance and high carbon emissions; however, the intense competition of hydrogen evolution reaction (HER) restricts the rate of NH3 production. Herein, amorphous Ni3B (a-Ni3B) is designed to balance the NRA and HER. The NH3 yield of a-Ni3B surpasses those of pure Ni and NiO, which is attributed to the preferential adsorption of NO3- on the B and Ni sites of a-Ni3B for the NRA reaction, greatly inhibiting the HER. Furthermore, the a-Ni3B possesses advantages in NRA performance compared to crystalline Ni3B (c-Ni3B) due to more active hydrogen (*H) generated during the catalytic process. The *H in the NRA process on a-Ni3B is verified by the electron spin resonance technique. The NRA mechanism is comprehensively discussed based on the results of in situ characterization and density functional theory calculations. The a-Ni3B can enhance NH3 production by inhibiting HER, which provides ideas for sustainable NH3 synthesis.

Transforming Food Biowaste into Selective and Reusable Adsorbents for Pesticide Removal from Water.

With growing concerns regarding environmental pollution and the need for sustainable waste management practices, this study investigates the potential of utilizing spent coffee grounds (SCG) as a precursor for producing functional carbon materials aimed at organophosphorus pesticide remediation under environmentally relevant conditions. Carbonization of SCG is followed by various activation methods, including treatment with potassium hydroxide, phosphoric acid, and carbon dioxide, individually or in combination. The resulting biochars are systematically analyzed for their adsorption performance towards malathion and chlorpyrifos. Screening tests revealed a selective adsorption preference towards aromatic chlorpyrifos over aliphatic malathion. Activation processes significantly influence adsorption kinetics and efficiency, with physical activation showing notable adsorption rates and capacity enhancements. Moreover, the SCG-derived biochars exhibit a pronounced dependency on adsorption temperature. Adsorption, regeneration, and reuse of the most promising material are tested in a real, spiked tap water sample, proving that the presence of ions in tap water did not affect the adsorption and that the material has the potential to be reused more than ten times. This work proposes a straightforward approach for recycling SCG by converting it into functional carbon materials, underscoring the importance of selecting the appropriate activation processes and conditions for practical applications in pesticide remediation.

Low-Energy Magnetic States of Tb Adatom on Graphene.

Electronic structure and magnetic interactions of a Tb adatom on graphene are investigated from first principles using combination of density functional theory and multiconfigurational quantum chemistry techniques including spin-orbit coupling. We determine that the six-fold symmetry hollow site is the preferred adsorption site and we investigate electronic spectrum for different adatom oxidation states including Tb3+, Tb2+,Tb1+, and Tb0. For all charge states, the Tb 4f8configuration is retained with other adatom valence electrons being distributed over 5dxy, 5dx2+y2, and 6s/5d0single-electron orbitals. We find strong intra-site adatom exchange coupling that ensures that the 5d6sspins are parallel to the 4fspin. For Tb3+, the energy levels can be described by theJ= 6 multiplet split by the graphene crystal field. For other oxidation states, the interaction of 4felectrons with spin and orbital degrees of freedom of 6s5delectrons in the presence of spin-orbit coupling results in the low-energy spectrum composed closely lying effective multiplets that are split by the graphene crystal field. Stable magnetic moment is predicted for Tb3+and Tb2+adatoms due to uniaxial magnetic anisotropy and effective anisotropy barrier around 440 cm-1controlled by the temperature assisted quantum tunneling of magnetization through the third excited doublet. On the other hand, in-plane magnetic anisotropy is found for Tb1+and Tb0adatoms. Our results indicate that the occupation of the 6s5dorbitals can dramatically affect the magnetic anisotropy and magnetic moment stability of rare earth adatoms.

Interfacial Thermoconvection and Atomic Relay Catalysis Enable Equilibrium Shifting and Rapid Glucose‐to‐Fructose Isomerization

AbstractThe aqueous glucose‐to‐fructose isomerization is controlled by thermodynamics to an equilibrium limit of ~50 % fructose yield. However, here we report an in situ fructose removal strategy enabled by an interfacial local photothermal effect in combination with relay catalysis of geminal and isolated potassium single atoms (K SAs) on graphene‐type carbon (Ksg/GT) to effectively bypass the equilibrium limit and markedly speed up glucose‐to‐fructose isomerization. At 25 °C, an unprecedented fructose yield of 68.2 % was obtained over Ksg/GT in an aqueous solution without any additives under 30‐min solar‐like irradiation. Mechanistic studies expounded that the interfacial thermoconvection caused by the local photothermal effect of the graphene‐type carbon and preferable glucose adsorption on single‐atom K could facilitate the release of in situ formed fructose. The geminal K SAs were prone to form a stable metal‐glucose complex via bidentate coordination, and could significantly reduce the C−H bond electron density by light‐driven electron transfer toward K. This facilitated the hydride shift rate‐determining step and expedited glucose isomerization. In addition, isolated K SAs favored the subsequent protonation and ring‐closure process to furnish fructose. The integration of the interfacial thermoconvection‐enhanced in situ removal protocol and tailored atomic catalysis opens a prospective avenue for boosting equilibrium‐limited reactions under mild conditions.

Merging experimental and theoretical approaches towards understanding real diesel fuel desulfurization by nanoporous carbons

Experimental tests combined with theoretical calculations have yielded new insights into real diesel fuel desulfurization (rDeSulfur) using activated nanoporous carbons. The carbons were selected for their varying physicochemical properties and further were chemically treated to modify their surface chemistry, aiming to investigate the impact of the major physicochemical features on rDeSulfur. The experimental findings demonstrated that both porosity and surface chemistry play complex roles. Specifically, a high degree of graphitization and diverse pore size distributions enhanced adsorptive capabilities, with some carbon samples achieving ultra-deep desulfurization levels (<1 ppmwS). Theoretical calculations indicated that π-π stacking through dispersion forces was the primary mechanism of adsorption. While surface functionalities at the edges of graphene had minimal impact on interaction strength, structural defects, especially clusters of three quaternary nitrogen atoms or single defected vacancy with OH group, improved interaction energies, boosting adsorption effectiveness compared to pristine graphene. The study concludes that the effectiveness of carbons in diesel desulfurization depends heavily on graphitization levels, defects, and where specific functionalities are located. Lastly, although aromatic compounds in diesel, like benzene, toluene, and naphthalene, compete with thiophenics for adsorption, they have lower interaction energies, suggesting preferential adsorption of sulfur compounds over the aromatics.

DFT calculations with and without spin polarization of the adsorption and decomposition of NCO and OCN on the Ag(110) surface

The adsorption of C, N, O, CO, CN, NCO and OCN, as well as the decomposition of NCO and OCN on the Ag(110) surface were studied using the density functional theory (DFT) with and without spin polarization combined with the periodic slab model, at a 0.25 ML coverage. Adsorption energy, preferred adsorption site, structural parameters, diffusion barrier of each species were determined. Work function and dipole moment changes of the Ag(110) surface allowed us to determine the direction of the charge transfer. We analyzed the interaction between the adsorbate and the surface, in the framework of the Local density of states (LDOS). Our results have revealed that the C, N and O atoms were stable on the top and hollow sites. The CN, NCO and OCN molecules bind strongly with the Ag(110) surface. While, the CO molecule weakly adsorbs on the Ag(110) surface. We found that the NCO and OCN thermochemical decomposition on the Ag(110) surface is not favorable. The CI-NEB calculations have also confirmed that the NCO and OCN decomposition on the Ag(110) surface was endothermic.

An efficient Ni-based adsorbent for selective removal of 85Kr and 14CH4 in radioactive contaminants from nuclear process off-gas stream

Efficient adsorbents for radioactive gas treatment in nuclear energy cycle is crucial for eliminating negative environmental impacts caused by wide nuclear applications. A Ni-based MOF material called JUC-86(Ni) which is based on 1-H-benzimidazole-5-carboxylic acid (HBIC) linker was synthesized for adsorbing the 85Kr, 14CH4 from off-gas stream. It was disclosed that there is a suitable pore environment for 85Kr and 14CH4 preferred adsorption in JUC-86 and the adsorption capacity could even reach 2.79 mmol/g (85Kr) and 2.54 mmol/g (14CH4) which are almost higher than all the adsorbents. The 85Kr/N2 and 14CH4/N2 IAST selectivities of the resulting sample are satisfactory (11.63 and 9.43) and well matched with the breakthrough experiments where the breakthrough times of 85Kr and 14CH4 are much longer than N2. What’s more, the adsorption heats of 85Kr and 14CH4 are less than 30 kJ/mol which indicated a stronger affinity than N2 and a low-energy regeneration. As simulation results showed that the adsorption distribution follows a-spiral-pattern which could be attributed to the N atom in the CN, this is also the dominant factor of the 85Kr and 14CH4 preferable adsorption.